This is because butterfly caterpillars are host specific. Plant-wise, the caterpillars of some butterfly species like asters, black-eyed Susan, clover, lupines, milkweed, sedum or violets. Aspen, birch, cherry, hackberry, oak or willow trees make caterpillars of other butterfly species equally happy.
each Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.ach Br-F bond would be polar or BF4-, there is an extra electron making this a polar molecule. PCl5 has the Cl atoms that must be as far apart from each other as possible and therefore would create equal but opposite pulls.
Basically, look at each bond in the molecule, and the greater the difference in the electronegativities of the atoms in the bond, the more polar that bond is. In three-dimensional space, some of the bonds may cancel each other out. For example, take CF4.All four of the C-F bonds are polar, but in the molecule as a whole, they are all cancel each other out due to how they are oriented spacially. CH2F2, though, polar.This is because there are two different kinds of bonds, which are two C-H bonds and two C-F bonds. There is a net polarity to the molecule because of this. An easy way to look at it is if all the atoms connected to the central atom are the same, as in CF4, then the molecule will not be polar.or example, take CF4. All four of the C-F bonds are polar, but in the molecule as a whole, they are all cancel each other out due to how they are oriented spacially. CH2F2, though, polar.